1. Field of the Invention
The present invention relates to an image forming apparatus and an image forming method for forming an image on a recording medium. More specifically, the present invention relates to an image forming apparatus and an image forming method each of which comprises: a recording head having aligned in a secondary scanning direction a plurality of dot forming sections each of which is a component for forming a dot on a recording medium; primary scanning portion for moving the recording head relative to the recording medium in a primary scanning direction intersecting the secondary scanning direction; and secondary scanning portion for moving the recording head relative to the recording medium in the secondary scanning direction, and each of which forms, on the recording medium, a subject image which is a predetermined image, by moving the recording head relative to the recording medium by means of the primary scanning portion and the secondary scanning portion.
2. Description of the Background Art
Conventionally, an image forming apparatus such as an ink-jet recording apparatus needs to have an enhanced resolution so as to improve a quality of an image to be formed, and various apparatuses and methods for realizing the enhancement of the resolution are suggested. For example, the ink-jet recording apparatus has limitations in enhancing the resolution by reducing a nozzle pitch (=a distance between two adjacent nozzles) of a recording head, and therefore it is suggested that recording is performed by using an interlace mode in which a record dot pitch smaller than the nozzle pitch is used.
Specifically, disclosed is an interlace-mode ink-jet recording apparatus in which primary scanning is performed multiple times in each of the nozzle pitches aligned in a recording head in a secondary scanning direction so as to record an image by using a record dot pitch (=a distance between two adjacent dots on a recording medium) which is smaller than a distance between two adjacent recording nozzles (see Japanese Laid-Open Patent Publication No. 11-245388).
On the other hand, in an ink-jet recording apparatus, some nozzles aligned in a recording head may be clogged with ink (so-called “nozzle clogging” may occur), and, in this case, an image having a high quality cannot be formed. Therefore, conventionally, a test pattern used for allowing visual determination as to whether or not a nozzle is clogged is formed on a recording medium such as recording paper on which an image is formed.
However, a conventional image forming apparatus such as the ink-jet recording apparatus disclosed in Japanese Laid-Open Patent Publication No. 11-245388 does not allow the visual determination of the nozzle clogging when an image is formed in the interlace mode because a distance between two adjacent dots is too narrow in the test pattern.